West Africa Doctors Network News Portal

Scientists may have finally found out why HIV infection is highest in sub-Saharan Africa, including Kenya, than other regions of the world.

The national fight against the spread of HIV/Aids, malaria and Tuberculosis (TB) has received over $63 million (approx Frw35 billion) grant support for the next two years.

Background: Malaria incidence has been reported to be falling in several countries in sub-Saharan Africa in recent years. This fall appears to have started before the widespread introduction of insecticide-treated nets. In the new era of calls to eliminate and eradicate malaria in sub-Saharan Africa, exploring possible causes for this fall seem pertinent.Presentation of the hypothesisThe authors explore an argument that presumptive treatment of fever cases as malaria may have played a role in reducing transmission of malaria by the prophylactic effect of antimalarials and their widespread use. This strategy, which is already in practise is termed Opportunistic Presumptive Treatment (OPT).Testing the hypothesisFurther comparison of epidemiological indicators between areas with OPT and more targeted treatment is required. If data suggest a benefit of OPT, combining long acting antimalarials that have an anti-gametocyticidal activity component plus using high levels of vector control measures may reduce transmission, prevent resistant strains spreading and be easily implemented. Implications of the hypothesisOPT is practised widely by presumptive treatment of fever in health facilities and home management of fever. Improving diagnosis using rapid diagnostic tests and thus reducing the number of doses of antimalarials given may have counter intuitive effects on transmission in the context of elimination of malaria in high to moderate transmission settings.

Australian scientists yesterday identified a potential treatment to combat malaria, a global scourge, which kills about 300,000 Nigerians, mostly children below five years, annually.

Providing schoolchildren with anti-malaria drugs once per term improves academic performance while reducing rates of infection and anaemia.

Background: Despite the abundance of studies conducted on the role of mosquitoes in malaria transmission, the biology and interaction of Plasmodium with its insect host still holds many mysteries. This paper provides the first study to follow the sporogonic cycle of Plasmodium vivax in a wild insecticide-resistant mysorensis strain of Anopheles stephensi, a major vector of vivax malaria in south-eastern Iran. The study subsequently demonstrates that host-parasite sugar binding interactions are critical to the development of this parasite in the salivary glands of its mosquito host. The identity of the receptors or sugars involved was revealed by a receptor "pre-saturation" strategy in which sugars fed to the mosquitoes inhibited normal host-parasite interactions. Methods: Anopheles stephensi mysorensis mosquitoes were artificially infected with P. vivax by feeding on the blood of gametocytaemic volunteers reporting to local malaria clinics in the Sistan-Beluchistan province of south-eastern Iran. In order to determine the inhibitory effect of carbohydrates on sporogonic development, vector mosquitoes were allowed to ingest blood meals containing both gametocytes and added carbohydrates. The carbohydrates tested were GlcNAc, GalNAc, arabinose, fucose, mannose, lactose, glucose and galactose. Sporogonic development was assessed by survival of the parasite at both the oocyst and sporozoite stages. Results: Oocyst development was observed among nearly 6% of the fed control mosquitoes but the overall number of mosquitoes exhibiting sporozoite invasion of the salivary glands was 47.5% lower than the number supporting oocysts in their midgut. Of the tested carbohydrates, only arabinose and fucose slightly perturbed the development of P. vivax oocysts at the basal side of the mosquito midgut, and the remaining sugars caused no reductions in oocyst development. Strikingly however, sporozoites were completely absent from the salivary glands of mosquitoes treated with mannose, GalNAc, and lactose. Conclusion: The study indicates that An. stephensi in southern Iran has the potential to survive long enough to be re-infected and transmit vivax malaria several times, based on the average adult female longevity (about 30 days) and its gonotrophic cycle (2-3 days) during the malaria transmission season. Certain sugar binding interactions are important for the development of P. vivax sporozoites, and this information may be instrumental for the development of transmission blocking strategies.

Background: Molecular markers, particularly those associated with drug resistance, are important surveillance tools that can inform policy choice. People infected with falciparum malaria often contain several genetically-distinct clones of the parasite; genotyping the patients' blood reveals whether or not the marker is present (i.e. its prevalence), but does not reveal its frequency. For example a person with four malaria clones may contain both mutant and wildtype forms of a marker but it is not possible to distinguish the relative frequencies of the mutant and wildtypes i.e. 1:3, 2:2 or 3:1. Methods: An appropriate method for obtaining frequencies from prevalence data is by Maximum Likelihood analysis. A computer programme has been developed that allows the frequency of markers, and haplotypes defined by up to three codons, to be estimated from blood phenotype data. Results: The programme has been fully documented [see Additional File 1] and provided with a user-friendly interface suitable for large scale analyses. It returns accurate frequencies and 95% confidence intervals from simulated dataset sets and has been extensively tested on field data sets. Conclusions: The programme is included [see Additional File 2] and/or may be freely downloaded from [1]. It can then be used to extract molecular marker and haplotype frequencies from their prevalence in human blood samples. This should enhance the use of frequency data to inform antimalarial drug policy choice.

Tanzania has started using Dichloro-diphenyl-trichloroethane (DDT) for Indoor Residual Spraying (IRS) from July this year.

THE Zimbabwe Defence Forces has stepped up training of medical officers in the uniformed forces to augment Government efforts in the fight against malaria.

Prof. Francis Omaswa is scheduled to address the British Parliament next Wednesday.

Background: Antibodies are the main effectors against malaria blood-stage parasites. Evaluation of functional activities in immune sera from Phase 2a/b vaccine trials may provide invaluable information in the search for immune correlates of protection. However, the presence of anti-malarial-drugs, improper collection/storage conditions or concomitant immune responses against other pathogens can contribute to non-specific anti-parasite activities when the sera/plasma are tested in vitro. Purification of immunoglobulin is a standard approach for reducing such non-specific background activities, but the purification method itself can alter the quality and yield of recovered Ag-specific antibodies. Methods: To address this concern, various immunoglobulin (Ig) purification methods (protein G Sepharose, protein A/G Sepharose, polyethylene glycol and caprylic acid-ammonium sulphate precipitation) were evaluated for their impact on the quality, quantity and functional activity of purified rabbit and human Igs. The recovered Igs were analysed for yield and purity by SDS-PAGE, for quality by Ag-specific ELISAs (determining changes in titer, avidity and isotype distribution) and for functional activity by in vitro parasite growth inhibition assay (GIA). Results: This comparison demonstrated that overall polyethylene glycol purification of human serum/plasma samples and protein G Sepharose purification of rabbit sera are optimal for recovering functional Ag-specific antibodies. Conclusion: Consequently, critical consideration of the purification method is required to avoid selecting non-representative populations of recovered Ig, which could influence interpretations of vaccine efficacy, or affect the search for immune correlates of protection.

Background: Falciparum malaria remains a major occupational illness that accounts for several deaths per year and numerous lost working days among the expatriate population, working or living in high risk malarious areas. Compliance to preventive strategies is poor in travellers, especially business travellers, expatriates and long-term travellers. Methods: In this cross-sectional, web-based study the adherence to and outcome of a preventive malaria programme on knowledge, attitudes and practices, including the practice of self-diagnosis and standby treatment (curative malaria kit, CMK) was evaluated in 2,350 non-immune expatriates, who had been working in highly malaria endemic areas. Results: One-third (N=648) of these expatriates visited a doctor for malaria symptoms and almost half (29 of 68) of all hospitalizations were due to malaria. The mandatory malaria training for non-immunes was completed by 92% of those who visited or worked in a high risk malaria country; 70% of the respondents at risk also received the CMK. The malaria awareness training and CMK significantly increased malaria knowledge [relative risk (RR) of 1.5, 95%CI 1.2-2.1], attitudes and practices, including compliance to chemoprophylaxis [RR=2.2, 95%CI 1.6-3.2]. Hospitalization for malaria tended to be reduced by the programme [RR=0.4, 95%CI 0.1-1.1], albeit not significantly. Respondents who did not receive instructions on the rapid diagnostic test were two times [RR=2.3, 95%CI 1.6-3.3] more likely to have difficulties. Those who did receive instructions adhered poorly to the timing of repeating the test. Moreover, 6% (31 of 513) of those with a negative test result were diagnosed with malaria by a local doctor. 77% (N=393) of the respondents with a negative test result did not take curative medication. 57% (252 of 441) of the respondents who took the curative medication that was included in the kit did not have a positive self-test or clinical malaria diagnosis made by a doctor. Conclusions: This survey demonstrated that a comprehensive programme targeting malaria prevention in expatriates can be effectively implemented and that it significantly increased malaria awareness.

THE World Health Organisation and the European Union have allowed Uganda to spray the DDT chemical, the water and environment minister has said.

Background: Artesunate-amodiaquine (AS+AQ) and artemether-lumefantrine (AM-L) are efficacious artemisinin combination therapy (ACT) regimens that have been widely adopted in sub-Saharan Africa. However, there is little information on the efficacy of these regimens on subsequent episodes beyond 28 days, or on the safety of repeated treatments. Methods: Children aged six months to 14 years with uncomplicated malaria were randomly assigned to treatment with AS+AQ (n=116), or AM-L (n=111). Recruited subjects were followed-up, initially for 28 days, and then monthly for up to one year. All subsequent attacks of uncomplicated malaria after 28 days were treated with the same regimen as at randomization. Investigations aimed at determining efficacy and side effects were conducted. Results: Adequate clinical and parasitological response in subjects with evaluable end-points were, 97.1% (100/103) and 98.2% (107/109) on day 14, and 94.2% (97/103) and 95.3% (102/107) on day 28 in the AM-L and AS+AQ groups, respectively. Similar results were obtained after PCR correction. The incidence of malaria attacks in the year following recruitment was similar between the two treatment groups (p=0.93).There was a high incidence of potentially AQ-resistant parasites in the study area. The incidence of adverse events, such as pruritus, fatigue and neutropaenia were similar in the two treatment groups. No patient showed signs of hearing impairment, and no abnormal neurological signs were observed during one year of follow-up. Other adverse events were mild in intensity and overlapped with known malaria symptomatology. No adverse event exacerbation was observed in any of the subjects who received multiple treatment courses with these ACT regimens during one year follow-up. Conclusions: AS+AQ and AM-L were efficacious for treatment of children with uncomplicated malaria in Ghana, and drug-related adverse events were rare in treated subjects during one year of follow-up. The high prevalence of potentially AQ resistant parasites raises questions about the utility of AQ as a partner drug for ACT in Ghana. The efficacy of AS+AQ in Ghana requires, therefore, continuous monitoring and evaluation.

Background: Malaria presents a diagnostic challenge in tribal belt of central India where two Plasmodium species, Plasmodium falciparum and Plasmodium vivax, are prevalent. In these areas, rapid detection of the malaria parasites and early treatment of infection remain the most important goals of disease management. Therefore, the usefulness of a new rapid diagnostic (RDT), the First Response(R) Combo Malaria Ag (pLDH/HRP2) card test was assessed for differential diagnosis between P. falciparum with other Plasmodium species in remote villages of Jabalpur district. Methods: A finger prick blood sample was collected to prepare blood smear and for testing with the RDT after taking informed consent. The figures for sensitivity, specificity, accuracy and predictive values were calculated using microscopy as gold standard. Results: Analysis revealed that overall, the RDT was 93% sensitive, 85% specific with a positive predictive value (PPV) of 79%, and a negative predictive value (NPV) of 95%. The accuracy 88% and J-index was 0.74. For P. falciparum, the sensitivity and specificity of the test were 96% and 95% respectively, with a PPV of 85% and a NPV of 99%. The RDT accuracy 95% and J-index was 0.84. For non-falciparum malaria, the sensitivity, specificity and accuracy were 83%, 94% and 92% respectively with a PPV of 69% and a NPV of 97%. Conclusion: The RDTs are easy to use, reliable and simple to interpret. RDTs are more suited to health workers in situations where health services are deficient or absent. Therefore, the test can be used as an epidemiological tool for the rapid screening of malaria.

Deputy High Commissioner at the British High Commission, Mr James Tansley, has commended the efforts of an international Voluntary Organization- Global Dream, in its consistent fight against malaria.

Malaria drugs worth of N21 million were released for free distribution by the Nasarawa state government yesterday.

The Federal Government and the United Kingdom will sign a £50m fund malaria project for five years in Nigeria .

THE Edo State Government has constituted a committee for the flag off of the newly approved free anti-malaria treatment for under-5 children and free antenatal care and anti-malaria treatment for pregnant women in the state.

Background: Artemisinin combination therapies (ACT), which are increasingly being introduced for treatment of Plasmodium falciparum malaria, are more effective against sexual stage parasites (gametocytes) than previous first-line antimalarials and therefore have the potential to reduce parasite transmission. The size of this effect is estimated in symptomatic P. falciparum infections. Methods: Data on 3,174 patients were pooled from six antimalarial trials conducted in The Gambia and Kenya. Multivariable regression was used to investigate the role of ACT versus non-artemisinin antimalarial treatment, treatment failure, presence of pre-treatment gametocytes and submicroscopic gametocytaemia on transmission to mosquitoes and the area under the curve (AUC) of gametocyte density during the 28 days of follow up. Results: ACT treatment was associated with a significant reduction in the probability of being gametocytaemic on the day of transmission experiments (OR 0.20 95% CI 0.16-0.26), transmission to mosquitoes by slide-positive gametocyte carriers (OR mosquito infection 0.49 95% CI 0.33-0.73) and AUC of gametocyte density (ratio of means 0.35 95% CI 0.31-0.41). Parasitological treatment failure did not account for the difference between ACT and non-artemisinin impact. The presence of slide-positive gametocytaemia prior to treatment significantly reduced ACT impact on gametocytaemia (p<0.001). Taking account of submicroscopic gametocytaemia reduced estimates of ACT impact in a high transmission setting in Kenya, but not in a lower transmission setting in the Gambia. Conclusions: Treatment with ACT significantly reduces infectiousness of individual patients with uncomplicated falciparum malaria compared to previous first line treatments. Rapid treatment of cases before gametocytaemia is well developed may enhance the impact of ACT on transmission.